Agni 1

Agni is the name of the protagonist of Fire Punch, a manga from 2016 by Tatsuki Fujimoto. He has the blessing of instant regeneration and at some point he becomes engulfed in flames that never go out. Due to his blessing he's constantly burning and regenerating himself so he's always on fire.

Agnimon (or Agunimon) from 'Digimon' bears this name.

There is a character called Agni in the manga/anime series "Kuroshitsuji" (Black Butler) by Yana Toboso. He is the butler of an Indian prince Soma Asman Kadar. He is called "The Right Hand of God" for his curry making skills and is able to stand equal in fight with a demon.

In the animated television series "Avatar: The Last Airbender" the Fire Nation has a traditional one-on-one battle called an Agni Kai, or Fire Duel.

Agni is the god of fire in Fire Nation mythology as well.